Abstract Molecular imaging methods can provide spatio-temporal information about the distribution of biomolecules or biological processes, such as certain enzymatic activities, in single cells. Within a cell, it is possible to define the subcellular location of a target, its trafficking through the cell, colocalization with other biomolecules of interest and involvement in certain cell biological processes. On the other hand, single-cell imaging promises to distinguish cells that are phenotypically different from each other. The corresponding cellular diversity comprises the presence of functionally distinct cells in a population (‘phenotypic heterogeneity’), as well as dynamic cellular responses to external stimuli (‘phenotypic plasticity’), which is highly relevant, e.g. during cell differentiation, activation (of immune cells), or cell death. This review focuses on applications of a certain class of chemical probes, the so-called activity-based probes (ABPs), for visualization of enzymatic activities in the single-cell context. It discusses the structure of ABPs and other chemical probes, exemplary applications of ABPs in single-cell studies in human, mouse and bacterial systems and considerations to be made with regard to data interpretation.

中文翻译：

---

所见即所得：酶活性单细胞分析中基于活性的探针

摘要 分子成像方法可以提供有关生物分子分布或生物过程（例如某些酶活性）在单个细胞中的时空信息。在细胞内，可以定义目标的亚细胞位置、其在细胞中的运输、与其他感兴趣的生物分子的共定位以及参与某些细胞生物过程。另一方面，单细胞成像有望区分表型彼此不同的细胞。相应的细胞多样性包括群体中存在功能不同的细胞（“表型异质性”），以及对外部刺激的动态细胞反应（“表型可塑性”），这是高度相关的，例如在细胞分化过程中，激活（免疫细胞）或细胞死亡。本综述侧重于某类化学探针的应用，即所谓的基于活性的探针 (ABP)，用于可视化单细胞环境中的酶活性。它讨论了 ABP 和其他化学探针的结构，ABP 在人类、小鼠和细菌系统的单细胞研究中的示例应用，以及对数据解释的考虑。